Method of making bags



Dec. 2, 1941...

' METHODOF MAKING BAGS Original Filed Decf 6, 19:59

I VP. KNUETTER" 2,265,075

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' Patented Dec. 2,1941

UNITED STATES PATENTOFFICE 2.265.075 mz'rnon or MAKING ands Paul Knuetter, Philadelphia, Pa assignor to Thomas M. Royal & Company, Philadelphia, Pa., a corporation of Pennsylvania Original application December 6, 1939, Serial No.

Divided and this application August 7; 1940, Serial No. 351,723

1 Claim. (01. 33-35) This invention relates to new and useful improvements in methods for making bags, and more particularly to the making of bags having an expansible square-like bottom' and comprising a single ply of heat-fusible material in which all seams of the bag are formed by fusion thereof, the same being a division co-pending application Serial No. 307,894, filed December 6, 1939;

The principal object of the present-invention is to provide a novel method of producing a bag having its seams disposed at the lateral side edges of the bag and provided with an expansible bottom capable of supporting the bag in an up- :right position. J Another equally important object of the invention is to provide a .novel method for producing ness of the heat-fusible sheet material therein a bag which is constructed and arranged so as to preclude the occurrence of pin holes at the junctionof the side seams and bottom of the bag.

These and other objects of the invention and the various features and details thereof are hereinafter more fully set forth and shown in the accompanying drawing, in which:

Figure 1 is aEview in perspective of a bag protogether as just described, a stronger bottom structure is obtained and a bag may be produced that is free from the possibility of the occurrence of pinholes at the junction of the side scams 4 and bottom.

In addition to-eliminating the occurrence of pin holes at the corners of the bottom of the bag, and generally affording a bottom structure of greater strength, the reentrant bottom fold or tuck 3 is, of course, expansible and thus when expanded provides the bag with a bottom quite duced by the process of the present invention showing the bottom thereof in open or expanded position. v

Figure 2 is a view in perspective of the bag shown in Figure 1 but in flat or collapsed position, certain portions of said bag being broken away td better illustrate various details of its construction.

Figure 3 is a diagrammatic view in perspective of one form of apparatus capable of carrying out the method of the present invention; and

similar to the conventional square type of bag bottom, thereby affording a base which permits the bag to be placed in astanding or upright position as well as rendering it more adaptable for receiving articles or material of a more or Figure 4 is an enlarged view in section taken on line 4-4," Figure 3. 7

Referring now to the drawing, and particularly Figures 1 and 2 thereof, a bag made according to the present invention is designated, l and comprises a single piece or sheet of thermolastic or heat fusible material 2 such as "pliofilm or the like which is substantially doubled upon itself and provided with an inward tuck or reentrant fold 3 transversely and inwardly of the bottom of the bag from edgeto-edge thereof. The lateral side edgesof the heat-fusible sheet material 2 are permanently fused together throughout the entire height of the' bag by the application of heat thereto to form the side seams l thereof and the upper end of said bag is left open as indicated at 5 to permit of the insertion of the desired articles or material therein.

- Upon leaving the forming disk or wheel 'Iythe folded edge of the doubled web is engaged by a less bulky nature.

Manufacture of the bag according to the present invention may be accomplished by drawing the web or sheet of heat-fusible material 2 from a vertically disposed supply .roll 6 and causing said sheet to be engaged by a wheel or disk I which functions to fold or double the'webv as shown in Figure 3 of the drawing. By vertical" adjustment of the disk I with respect to the web 2 the extent to which the folded or doubled portions of said web lap one another may be regulated as desired to provide the mouth of the bag with a projecting'lip or not, as desired.

tucking element 8 which functions to form a longitudinally extending inward tuck or reentrant fold -3 therein of desired depth after which the folded and tucked web is drawn between. a pair of opposed draw-rolls 9 and ill and thence between rollers ii and I2; the latter being provided with a heating element i3 comprising a pair of closely spaced parallel narrow portions I31) and l3c which engage the doubled web transversely thereof and fusibly. seal together the thickness of said web in relatively narrow closely spaced zones [4, ll transversely -mined spaced intervals therealong. I V .a

The web thus fused together transversely at over the entirewldth of said web at predeterperiodic intervals is then conveyed-as shown to a cut-off mechanism comprising a lower stationary cutting element" ligand an upper revolving cutting element I 6 carried by a'roller' ll and'drivenin timed relation to the sealing element l3 so-that bags I are cut from the web alonglines transversely thereof and intermediate the pairedtransversefused zones H, II.

intended that said'invention shall be limited to such disclosure but' that changes and modifications may be'made and embodied therein within the scope of the annexed claim.

I claim: --In the method of making open-mouth bags, the steps comprising advancing a web of heat- 7 fusible material, angular-1y deflecting and 611888! The resulting bags I now ready for-use, may

material to be packaged, the tuck or ree trant be opened and, upon insertion of the'artgtgle or fold 3 lsexpanded as shown in Figure 1 pre ent; ing a substantially flat bottom surface capable of supporting the bag in an upright position.

ing said web along a line longitudinally thereof 'and intermediate its side edges to fold said web into a doubled web in which the thicknesses of said doubled web lap one another in predeterj mined relation with the free edges thereof -residing adjacent one side of the doubled web and defining therebetween the open mouths of the bags, engaging the folded edge portion of the Bags produced according to the present invitation have'the chief advantages of conventional square-bottom bags and at the same time the construction of the bags is such that the occurrence or formation of pin holes in the seam' corners is preventedwhile all of the advantages I of a moisture-proof sealed bag constructed are retained; -After' packaging, the-goods may be sealed within the bag by fusing together the adjacent surfaces of the thermoplastic material at the .top of the bag in the conventional ,manner.

While a particular embodiment of the invenweb with a member operable to tuck said folded edge portion inwardly of the lapped portions of said web to provide a reentrantiold longitudinally thereof, transversely heat-sealing 'the doubled'reentrant folded web from edge to edge thereof in pairs of relatively narrow closely spaced zones spaced. at' intervals along said doubled web, and then severing open-mouth bags I from said doubled web transversely thereof in the spaces. residing between .the narrow closely spaced, pairs of transverse heat-sealed zones of the web.

. PAUL KNUE'II'ER. 

